The vulnerable, elderly population residing in U.S. nursing homes (NHs) is anticipated to grow from 1.5 million today to 5.3 million by 2030. This population poses significant demand for care as 45% of NH residents are older than 85 years and 90% of residents are frail. As the number of NH residents over the age of 85 will continue to increase, it is critical to understand the needs of this group to anticipate future care challenges. Infections are the leading cause of morbidity and mortality in NHs, are difficult to eliminate, and expensive to treat, although often avoidable. Infections represent a significant burden on NH residents as well as the overall healthcare system as elderly NH residents are at high risk for infection in general and multi-drug resistant organism (MDRO) infections in particular. Enhancing knowledge supporting MDRO infection management and control is important because MDRO infections are particularly difficult and costly to treat. Despite this, acute care has been the primary focus of infection prevention research. Implementation of effective infection prevention strategies to reduce preventable MDRO incidence in NHs is essential. Isolation precautions are the preferred technique to control MDRO transmission in NHs, but have specific drawbacks and have been not been adequately studied in NHs. Data supporting use of isolation precautions to prevent MDRO infection were collected in acute care settings and therefore may not apply to residential community settings such as NHs. Therefore, it is necessary to confirm the benefits of this practice. The proposed study will be the first to evaluate nationwide isolation precaution use and MDRO infection risk in NHs and thus has the potential to overcome barriers to external validity encountered by previous studies. Guided by the Quality Health Outcomes conceptual framework, the proposed study aims to identify system and client characteristics that predict MDRO infection probability and isolation precaution use. Furthermore, it also aims to determine the relationship between isolation precautions use and MDRO infections in NH. The study will include residents of freestanding NHs certified to accept CMS reimbursement in 2011. Multi-level logistic regression models will address the three aims. Given the proposed study design to use large, national datasets, this study has the potential to provide stronger evidence than all previous investigations of MDROs or isolation precautions in NHs. The proposed study addresses NINR's goals to promote the ability of clinician, client, and community to balance multiple determinants of health in maximizing disease prevention and health promotion in a vulnerable population. Furthermore, the proposed study is aligned with goals of the Ruth L. Kirschstein National Research Service Award (NRSA) for individual pre-doctoral fellowships as it will provide valuable experience and accelerate the career of a BSN to PhD nurse scientist committed to pursuing health-outcomes research.